Dozens hurt as blast rocks shopping complex in Nairobi

Members of the public assist firefighters at the scene of a blast in central Nairobi, Kenya on May 28, 2012.

Updated at 10.05 a.m. ET -- Reuters reports — A blast struck a shopping complex in Nairobi's business district during Monday's lunch hour, wounding more than two dozen people, but there was confusion over whether the explosion was caused by a bomb or electrical fault.

Police Commissioner Mathew Iteere told reporters it was too early to determine the cause of the blast. He said blackened wires inside the trading center indicated a possible electrical fault and ruled out a grenade attack.

Two shopkeepers, however, told Reuters independently that they saw a man drop a bag inside the trading center moments before the blast.

"He came into the shop twice, looking at T-shirts. He said he didn't have money so he left. Then he came back," said Irene Wachira. "(He was) three shops away from where I was. He left a bag and a few moments later we had an explosion. The roof caved in and debris started falling on us," Wachira said.

Civilians attempt to extinguish a fire in a clothing shop after the explosion. Dense black smoke billowed from the badly damaged building and sirens blared as emergency service crews rushed to Moi Avenue, a major road running through the city center.